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WorksheetsUnit 5 - Gene Expression Study Guide
Total questions: 120
Worksheet time: 57mins
Which process converts DNA into a complementary RNA sequence?
Replication
Translation
Transcription
Duplication
Which base correctly pairs with adenine during transcription?
Cytosine
Uracil
Thymine
Guanine
If a DNA strand is TAC GGC TTA, the mRNA produced will be—
ATG CCG AAT
AUG GGC UUA
UAC CCG AAU
AUG CCG TTT
Which type of RNA carries amino acids to the ribosome?
mRNA
rRNA
tRNA
snRNA
Which molecule acts as the “blueprint” for making proteins?
Lipids
DNA
tRNA
ATP
Cell specialization is determined primarily by—
which genes are expressed
the number of genes present
the size of the nucleus
mitotic rate
During translation, the codon AUG always codes for—
Stop
Proline
Methionine
Histidine
Which statement best describes gene expression?
Every cell expresses every gene.
Only certain genes are activated in each cell type.
Genes change sequence to match the cell.
Proteins turn into DNA.
Which environmental factor can influence gene expression in plants?
Gravity
Sunlight
Wind speed
Soil color
What is the correct order of information flow in the central dogma of biology?
Protein → RNA → DNA
RNA → DNA → Protein
DNA → RNA → Protein
RNA → Protein → DNA
Stem cells can form many cell types because they—
lack DNA
are undifferentiated
contain fewer chromosomes
use
Which RNA base sequence complements DNA ATT CGA?
UAA GCU
TAA GCT
AUA CGT
UUA CGA
What happens to mRNA before it leaves the nucleus?
Its introns are removed.
It binds amino acids.
It becomes double-stranded.
It dissolves ribosomes.
Which process occurs at the ribosome?
Replication
Transcription
Translation
Duplication
Why do lens cells and muscle cells in the same organism look and function differently?
They contain different genes.
They express different genes.
Their DNA sequences differ.
One lacks a nucleus.
Which molecule directly determines the sequence of amino acids in a protein?
DNA
mRNA
rRNA
ATP
Which event marks the beginning of gene expression?
Replication of DNA
Binding of RNA polymerase
Formation of ribosomes
Translation termination
An mRNA codon is UAC. Its complementary tRNA anticodon will be—
AUG
TAC
GUA
CAU
Which statement about enzymes and gene expression is true?
Enzymes are coded by specific genes.
Enzymes copy genes into DNA.
Genes form enzymes directly.
All genes code for the same enzyme.
What is the function of RNA polymerase?
Join amino acids
Unzip DNA and add RNA nucleotides
Synthesize DNA
Transport tRNA
A student claims transcription errors never matter because they aren’t inherited. Which correction is accurate?
They can still affect protein production in that cell.
They are immediately repaired by ribosomes.
They change the organism’s offspring.
They cause chromosomal duplication.
In a developing embryo, cell fate depends mainly on (a) .
gene activation patterns
mutation rate
mitosis speed
protein digestion
What happens after mRNA leaves the nucleus?
It binds to ribosomes for translation.
It is degraded immediately.
It unzips DNA.
It joins tRNA molecules.
The sequence of three bases on mRNA that codes for one amino acid is a—
gene
anticodon
codon
chromatid
Which best describes the purpose of gene regulation?
To activate every gene
To allow cells to respond to environmental changes
To mutate DNA
To stop protein synthesis
A mutation that substitutes one base for another is called a—
Frameshift mutation
Point mutation
Insertion mutation
Deletion mutation
Which mutation results in an entirely different amino-acid sequence after the change?
Substitution
Insertion
Nonsense
Silent
A mutation changing a codon to a stop codon is a—
Missense
Nonsense
Silent
Frameshift
Which type of chromosomal mutation reverses gene order on the same chromosome?
Deletion
Inversion
Translocation
Duplication
If a segment of DNA breaks off one chromosome and attaches to another non-homologous chromosome, it is—
Duplication
Translocation
Deletion
Inversion
Which statement best explains why most mutations are neutral?
They occur in noncoding regions or result in the same amino acid.
They always enhance protein function.
They are quickly repaired by the cell.
They lead to beneficial traits.
After bacteria were exposed to UV light, some developed antibiotic resistance. What explains this change?
They inherited traits from nearby bacteria
They became resistant through adaptation only
A beneficial mutation occurred and was selected for
The light sterilized weak bacteria
Match the following genetic changes with the conditions they result in:
A deletion of a single gene
Cystic fibrosis results from—
A substitution that changes one amino acid in hemoglobin
Sickle-cell anemia results from—
A duplication of a chromosome
Down syndrome results from—
A translocation between chromosomes 9 and 22
Chronic myeloid leukemia results from—
Which mutation is heritable and can be passed to offspring?
A gametic (sex-cell) mutation
A somatic mutation
A skin-cell mutation
A nerve-cell mutation
Which chromosomal mutation removes a section of genes?
Deletion
Duplication
Inversion
Translocation
Cystic fibrosis is caused by the loss of three bases in the CFTR gene. This mutation is classified as—
Deletion
Insertion
Substitution
Duplication
Why are frameshift mutations typically more harmful than substitutions?
They only affect one amino acid
They shift the reading frame, changing all codons after the mutation
They duplicate a single gene
They never alter amino acids
Which factor increases the likelihood of mutations in DNA?
Exposure to sunlight
Exposure to radiation and mutagenic chemicals
Balanced diet
Rest during cell division
A deletion in a skin cell’s DNA would most likely—
Affect only that cell and its daughter cells
Be passed to the next generation
Repair itself during mitosis
Alter gametes permanently
A substitution mutation that still codes for leucine is known as a—
Missense
Silent
Nonsense
Frameshift
Why are mutations important to evolution?
They always cause disease.
They destroy harmful traits.
They create genetic variation for natural selection.
They prevent adaptation.
What is the Philadelphia chromosome?
A duplication linked to cystic fibrosis
A translocation between chromosomes 9 and 22 linked to leukemia
A deletion found in Down syndrome
An inversion linked to sickle-cell anemia
Which of the following is a chemical mutagen?
Tobacco smoke
X-rays
UV radiation
High temperature
Which of the following is a physical mutagen that causes thymine dimers?
Ultraviolet (UV) radiation
Tobacco tar
Carbon dioxide
Nitrous acid
The ultimate source of all new genetic variation is (a)
Crossing over
Independent assortment
Fertilization
Mutation
Which event can cause a change in chromosome number?
Inversion
Translocation
Nondisjunction during meiosis
Duplication
Gametic mutations differ from somatic mutations because they—
Occur after birth
Can be passed to offspring
Are always fatal
Never affect genes
Which type of cell could pass a mutation to the next generation?
Egg cell
Skin cell
Nerve cell
Muscle cell
If replication errors are not corrected by DNA repair enzymes, what results?
The cell immediately dies.
A permanent mutation in the DNA sequence.
The RNA is altered.
The protein dissolves.
Which group of enzymes repairs errors in DNA?
RNA polymerase and helicase
Ribosomes and ligase
DNA polymerase and ligase
tRNA and primase
A chromosomal duplication results in—
Loss of genetic information
Extra copies of certain genes
Genes switching positions
Complete chromosome loss
A missing part of chromosome 5 causes Cri-du-chat syndrome. This is an example of—
Duplication
Inversion
Deletion
Translocation
A large inversion on a chromosome can disrupt gene regulation because—
The chromosome breaks during mitosis
Gene sequences are reversed, altering expression
Proteins replace missing bases
Codons are shifted one base forward
Mutations in genes that code for DNA-repair enzymes often lead to—
Faster cell division
Cancer and accumulation of DNA damage
Increased fertility
Neutral genetic variation
Why can radiation therapy damage healthy tissue near a tumor?
It causes dehydration of healthy cells
It increases blood pressure
It induces mutations in normal DNA
It prevents mitosis from ending
When DNA polymerase fails to proofread properly, the result is—
A chromosomal translocation
A neutral gene
A spontaneous mutation
A duplicated chromosome
If a mutation alters an mRNA molecule but not the DNA sequence, the effect—
Becomes permanent
Affects only proteins made from that transcript
Spreads to all daughter cells
Is inherited through gametes
Beneficial mutations are important because they—
Usually cause disease
Prevent adaptation
Provide advantages that can be selected for over generations
Reduce genetic diversity
Neutral mutations are defined as those that—
Destroy enzymes
Benefit only one species
Have no effect on phenotype or fitness
Always occur in coding DNA
In humans, Down syndrome most often results from (a)
Why can chromosomal mutations have greater effects than gene mutations?
They occur later in development
They involve many genes and regulatory regions
They only affect mRNA
They are easier to repair
Which outcome could follow a mutation in a regulatory gene?
Chromosome shortening
Faster DNA replication
Abnormal levels of protein production
Improved enzyme proofreading
Why aren’t all mutations expressed in an organism’s traits?
All are repaired
Some occur in non-coding DNA or are silent
They never reach RNA
They duplicate chromosomes
What can cause mutations during meiosis?
Cytokinesis errors
Nondisjunction or errors in crossing-over
mRNA splicing
Mitotic checkpoints
Which medical condition most likely results from a translocation?
Down syndrome
Certain leukemias and cancers
Cystic fibrosis
Sickle-cell anemia
If a mutation changes the shape of a protein, what effect may occur?
The protein gains more amino acids
Translation stops permanently
The protein may lose its normal function
The DNA sequence repairs itself
When a gene is duplicated, one copy may—
Be deleted immediately
Reverse its base order
Evolve a new function over time
Prevent the other from working
A mutation that increases the efficiency of an enzyme’s activity is considered—
Harmful
Neutral
Beneficial
Artificial
Which type of mutation is most likely lethal to an organism?
Silent substitution
Frameshift in an essential gene
Duplication in a noncoding region
Single-base insertion in tRNA
When can a mutation be corrected by repair enzymes?
After cell division
During transcription
Before DNA replication is complete
During meiosis
Radiation, chemicals, and certain viruses are all examples of—
Carbohydrates
Codons
Mutagens
Alleles
Cancer often arises because of mutations in genes that—
Control digestion
Regulate the cell cycle or suppress tumors
Code for tRNA
Replicate viral DNA
In a cold environment, a mutation that could provide an adaptive advantage is (a)
Which process ensures most DNA replication errors are corrected before cell division?
RNA splicing
Proofreading by DNA polymerase
Codon pairing
Translation editing
Why are some mutations described as “silent”?
They always destroy DNA
They occur only in tRNA
They do not change the amino-acid sequence of the protein
They affect every codon in the sequence
Which biotechnology tool cuts DNA at specific sequences?
DNA ligase
Restriction enzyme
RNA polymerase
Helicase
Polymerase Chain Reaction (PCR) is used primarily to—
Separate DNA fragments
Amplify tiny DNA samples into millions of copies
Cut DNA into equal lengths
Replace faulty genes in humans
Gel electrophoresis separates DNA fragments based on their—
Age
Enzyme activity
Size and electrical charge
Type of nitrogen base
CRISPR technology allows scientists to—
Observe protein folding
Edit or disable specific genes precisely
Copy RNA into DNA
Clone whole organisms
Why can a frog gene function properly inside bacterial cells?
They share the same cell structures
The genetic code is universal among all organisms
Frog proteins fold faster
Bacteria have extra chromosomes
(a) identifies individuals by comparing DNA banding patterns.
Recombinant DNA refers to—
DNA that has been replicated
DNA formed by combining genes from two organisms
Mutated DNA
Deleted chromosomes
How do scientists produce human insulin using biotechnology?
By selective breeding of humans
By inserting the human insulin gene into bacteria that produce it
By cloning pancreatic cells
By using X-rays to activate insulin genes
Which protein is commonly mass-produced using genetic engineering?
Collagen
Hemoglobin
Insulin
Myosin
Which human protein is not typically produced using biotechnology?
Human growth hormone
Insulin
Hemoglobin
Clotting factor VIII
What benefit do herbicide-resistant crops provide farmers?
They prevent soil erosion
They require no sunlight
They survive herbicide sprays that kill weeds
They eliminate all pests
A plasmid containing both bacterial and human DNA is an example of—
RNA sequencing
Genetic engineering using recombinant DNA
Translation
Transformation error
Which step occurs first when creating a genetically modified organism (GMO)?
Insert the plasmid into host cells
Grow modified cells in culture
Identify and isolate the target gene
Harvest desired proteins
A student discovers E. coli expressing a human gene makes an identical protein. What does this show?
Genes can change between species
The genetic code is shared by all living things
Only bacteria express human genes
Human DNA mutates quickly
Which biotechnology process can treat some genetic disorders by replacing faulty genes?
DNA fingerprinting
Cloning
Gene therapy
Gel electrophoresis
Why is biotechnology valuable in modern agriculture?
It reduces photosynthesis
It increases soil salinity
It enhances crop yield and disease resistance
It eliminates genetic diversity
What is the role of vectors such as plasmids in biotechnology?
They cut DNA
They translate mRNA
They deliver foreign genes into host cells
They destroy unwanted proteins
Match each scientific field with the type of work or evidence it is most associated with.
Evolutionary biology
Study of how species change over time
Cytology
Examination of cells and their structure
Forensic science
Identification of individuals using DNA evidence
Embryology
Study of development from fertilization to birth
Which biotechnology allows scientists to detect pathogens rapidly in a patient sample?
Gel electrophoresis
PCR amplification and sequencing
Gene therapy
RNA interference
What is a major ethical concern surrounding genetic engineering?
It prevents genetic diversity
It reduces crop yield
It may create unintended ecological or health effects
It has no real benefits
How do government agencies ensure the safety of genetically modified foods?
By banning biotechnology research
Through regulatory testing, labeling, and approval standards
By limiting all exports
By eliminating herbicide use
Cloning animals such as Dolly the sheep relied on—
Cross-breeding
Transferring a nucleus from a body cell into an enucleated egg cell
Radiation exposure
Bacterial conjugation
Biotechnology that repairs or replaces defective genes in humans is known as—
DNA sequencing
Gene therapy
Recombinant cloning
DNA extraction
Which laboratory process creates identical DNA copies outside a living organism?
Gel electrophoresis
DNA replication
Polymerase Chain Reaction (PCR)
Transformation
How do studies of mutations and biotechnology together support the theory of evolution?
They show evolution stops in modern species
They prove all mutations are harmful
They demonstrate that DNA changes create variation that drives adaptation over time
They eliminate natural selection
A mutation within the promoter region has occurred. What would potentially happen to transcription rate?
Mutated promoters decrease the rate of transcription.
Mutated promoters increase the rate of transcription.
Mutated promoters can increase or decrease the rate of transcription.
Mutated promoters cease transcription of the adjacent gene.
A lack of this nonprotein molecule would result in the inability of the cell to "turn off" genes:
Operon
Inducer
Promoter
Repressor
Corepressor
A mutation in this section of DNA could influence the binding of RNA polymerase to the DNA:
(a)
The lactose operon is likely to be transcribed when
there is more glucose in the cell than lactose.
the cyclic AMP levels are low.
there is glucose but no lactose in the cell.
the cyclic AMP and lactose levels are both high within the cell.
the cAMP level is high and the lactose level is low.
How does active CAP induce expression of the genes of the lactose operon?
It terminates production of repressor molecules.
It degrades the substrate allolactose.
It stimulates splicing of the encoded genes.
It stimulates the binding of RNA polymerase to the promoter.
Muscle cells differ from nerve cells mainly because they
express different genes.
contain different genes.
use different genetic codes.
have unique ribosomes
The protein that performs RNA splicing by removing introns and connecting exons is called a(n) (a) .
Which of the following is characteristic of the product of the p53 gene?
It is an activator for other genes.
It speeds up the cell cycle.
It causes cell death via apoptosis.
It allows cells to pass on mutations due to DNA damage.
It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.
The cancer-causing forms of the Ras protein are involved in which of the following processes?
Relaying a signal from a growth factor receptor
DNA replication
DNA repair
Cell cycle control system
Attachment of ______ groups to ______ will cause promotion of gene expression due to looser DNA.
acetyl, DNA
methyl, DNA
acetyl, histones
methyl, histones
The noncoding sequence of DNA located within the promoter where RNA polymerase will bind is called the (a) .
A type of control element that acts with transcription factors to promote initiation may be perceived as a distal control element. This control element is called a(n):
(a)
All of the following occur before mature RNA is formed except:
Addition of a poly-A tail
Addition of a 3' cap
Addition of a release factor
Removal of introns
Alternative splicing
The sequence of nucleotides complementary to one located on mRNA that is carried by tRNA towards the translation site is called a(n):
(a)
Proteins targeted for degradation are tagged with (a) before they are recognized by proteasomes.
The function of siRNAs is to:
play a role in RNAi
contribute to euchromatin formation
degrade mature RNA
contribute to forming mutations in the promoter sequence
Cancerous genes that have undergone some type of transformation from their normal counterparts through mutations are called (a) .
The protein that functions in unwinding DNA strands before replication occurs is called:
Topoisomerase
Single-strand binding proteins
Helicase
Ligase
Spliceosome
The mitotic division undergone by only prokaryotes, such as bacteria is known as (a) .
A type of hereditary pattern exhibited by the coat colors of Labrador retrievers shows a phenotypic ratio of 9:7. This type of pattern is known as:
Polygenetic inheritance
Multiple alleles
Codominance
Incomplete dominance
Epistasis
